Railway-traffic-controlling apparatus



H. A. THOMPSON RAILWAY TRAFFIC CONTROLLING A'PIARATUS May 10, 1927. 1,628,287

Filed Jan. 25. 1926 Fig. 2!

a !NVENTO R'.

- PM QZ'M mg, I IMATTORNEY Patented May 10, 1927.

UNITED STATES PATENT OFFICE.

HOWARD A. THOMPSON, OF WILKINSBURG, PENNSYLVANIA, ASSIGNOR TO THE UNION SWITCH & SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORATION or PENNSYLVANIA;

RAILWAY-TRAFFIC-CONTROLLING APPARATUS.

Application filed January 25, 1926. Serial No. 83,441.

My invention relates to railway traflic controlling apparatus, and particularly to apparatus of the type comprising train carried governing means controlled by energy re ceived from the trackway. More particularly my invention relates to the trackway portion of such apparatus.

I will describe two forms of trackway apparatus embodying my invention, and

will then point out the novel features thereof in claims.

In the accompanying drawing, Fig. 1 1s a diagrammatic view illustrating one form of trackway apparatus embodying my invention. Fig. 2 is a view showing a modified form of the trackway apparatus illustrated in Fig. 1 and also embodying my invention.

Similar reference characters refer to similar parts in both views. 1 Referring first to Fig. 1, the reference characters 1 and 1 designate the track rails of a stretch of railway track over. which triflic normally moves in the direction indicated by the arrow. These rails are divided by means of insulated joints 2 into a plurality of successive sections AB,. BC, etc. Each track section is provided with a suitable source of track circuit current, such as a battery, designated by the reference character D with a distinguishing exponent and connected across the rails adjacent the exit end of the associated section in series with the usual resistor 10 and a reactance 11. Each section is also provided with a track relay connected across the rails adjacent the entrance cnd'of the section and designated by the reference character R with an exponent corresponding to the location.

Means are also provided for supplying train controlling current to each track section. As here shown this current is supplied to each section in part by a train control transformer designated by the reference character T with a suitable distinguishing exponent. Each train control transformer T comprises a primary 9 which is constantly supplied with alternating current from a suitable source of current, such as an alternator M, over line wires 3 and 3*. Each transformer T also comprises twosecondaries 7 and 8, one of which, 7,-is constantly connected across the track rails in series with 12 of relay R resistor 10, reactance 11 and the associated of the exit end of the section such for example, as 100 or 200 feet. A transformer K has its secondary 4 connected across each insulated joint 2* in series with a reactance 6.

Each section is further provided with a second track relay R connected across the rails adjacent insulated joint 2'' on that side of the joint which is adjacentthe exit end of the corresponding section.

The primary 5 of each transformer K is provided with alternating current from the secondary 8 of the associated train control transformer T. Referring particularly to transformer K the primary 5 of this transformer is provided with a circuit including secondary 8 of the transformer T a'front contact 13 of relay R and a front contact It follows therefore that primary 5 of transformer K is supplied with alternating current only when relays R and R are both energized.

The trackway apparatus illustrated in the drawing is suitable for co-operation with train carried governing apparatus which is arranged to control automatic brake applying mechanism on the train. When the train carried apparatus is being supplied with train controlling current from the trackway the brake applying mechanism is prevented from causing an automatic application of the brakes. If however, the supply of train controlling current is interrupted, or if the magnitude of this current is reduced below ondary 'i' of transformer T It will be observed that the currentsupplied to the rails of section B C by secondary 7 must traverse reactance 6 and secondary 4 of transformer K The parts are so proportioned that under these conditions the magnitude of the current supplied to section B'C is below the predetermined value necessary to prevent an ZtHtOD'lfltiC application of the brakes.

Current supplied to the rails of section BC by battery D energizes relay R Relay R is also energized by current supplied lay R from rail I this train controlling current flows back to secondary l of transformer K Train controlling current is also supplied to the rails of sect1on A-B .by secondary 7 of transformer T I will now assume that a train moving in the direction of the arrow enters section AB. The train controlling current supplied to the rails of this section by transformers K and T is sufficient to prevent an automatic application of the brakes and the train is therefore permitted to proceed through the section without diminishing its speed. As the train passes point X relay R becomes de-energized thereby interrupting the circuit for transformer K It follows that while the first train is between X and B, if a second train should attempt to enter section AB it would not be supplied with train controlling current and the brakes would be applied unless the engineman should acknowledge. The train controlling current supplied to the rails of section B-C is not sufiicient to operate the train carried governing apparatus and the brakes are therefore applied when the train passes point B unless the engineman acknowledges. As this train passes point Y however the wheels and axles of the train shunt out reactance 6 and secondary 4 of transformer K from the circuit of secondary 7 of transformer T and the impedance of this circuit is therefore materially decreased and the train controlling current flowing in the rails is correspond ingly increased. to the value required to operate the train governing apparatus. As the train enters the section to the right of point C it is again deprived of train controlling current due to the shunting effect of the wheels and axles of the train V. An

6 are therefore short circuited.

automatic application of the brakes will therefore again be incurred unless the engineman acknowledges.

It should be pointed out that should a break occur between secondary 7 of any transforn'icr T and the rails of the corresponding section or in either of the rails between the exit end of the section and the intermediate pointllQ'Y, etc., the train controlling current supplied to the rails of that section by such transformer T would be interrupted. The train controlling current then supplied to the section by the associated transforn'ierK would be reduced because one part of this current normally flows through the-secondary of the transformer T forthe same section. The train controlling current therefore is reduced in magnitude between the entrance end of the section and the intermediate point X, Y, etc, and is completely discontinued between the intermediate point and the exit end of the section. It is evident therefore that unless the circuit supplied by secondary 7 of transformer T isintact and is actually being supplied with train controlling current, it will be impossibleto supply train controlling current to the section between the entrance end thereof and the intermediate point X, Y, etc.

If a break should occur between secondary 4 of transformer K'and the rails of the associated section, it would interrupt the circuit for current from transformer T and the supply of train control current to the section would be discontinued.

Furthermore, should the circuit for primary 5 of any transformer K become interrupted, it would be impossible to supply train controlling current to the section at the intermediate point X, Y, etc.

It will therefore be clear that the circuits are completely checked and that should a fault occur in any of the circuits it would be impossible for a train to proceed through the associated section without incurring,an automatic application of the brakes.

Under some conditions itmight happen that one of the insulated joints 22 would break down. For example, I will. assume that joint 2 at point Y breaks down. Sheondary f of transforn'ier K" and reactance Current from secondary 7 flowing in the rails of section BC will then be of sullicient magnitude to operate the train carried governing apparatus. If, therefore, a train enters sec tion BC under those conditions the brakes will not be applied even if the primary circuit for transforimu' K" is open due to the presence of a train in the section to the right of point (1. This dangerous condition may be eliminated by arranging the apparatus as shown in Fig. 2.

Referring to Fig. 2, it will be seen that both rails 1 and 1 are provided with insulated joints 2 at the intermediate points, X, Y, etc. Referring particularly to section A-B, rail 1 in rear of point X is connected with rail 1 in advance of this point by means of conductor 14, and rail 1 in advance of point X is connected with one terminal of secondary 4. of transformer K The other terminal of secondary 4 is con nected through reactance 6 with rail 1 in rear of the insulated joints 2. It will be plain from the drawing that with the circuit arranged in this manner current from transformer K flows through the rails of the section AB in series as before but that with this arrangement should either of the insulated joints 2 break down the secondary 4 of transformer K will not be short circuited. For example I will assume that joint 2 in rail 1 of section AB breaks down. Relay R is then shunted so that front contact 12 opens and breaks the circuit of primaryfi of transformer K Furthermore, the train controlling current supplied to the rails by secondary 7 of transformer T now flows down one rail to conductor 14 and back the other rail to secondary 7 and is greatly reduced in that portion of the section to the left of oint X. A train entering the section un er these conditions without acknowledgment would therefore receive an automatic application of the brakes. Similarly, if the insulated joint 2 in rail 1 should break down, the rails to the left of point X would be connected together and train controlling current would be shunted away from the left-hand end of the section AB so that a train entering this section would receive an automatic application of thebrakes. It will be plain that with the apparatus shown in this drawing complete protection is afforded against all possible failures.

Although I have herein shown and described only two forms of railway traflic controlling apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. Railway trafiic controlling apparatus comprising a stretch of railway track, a source of track circuit current for said stretch, a, transformer having a primary constantly supplied with alternating current and two secondaries, means for constantly connecting one said secondary with the rails of said stretch, and means for at times supplying train controlling current from the other said secondary to at least one rail of said stretch.

2. Railway trafiic controlling apparatus comprising a stretch of railway track, a

source of track circuit current forsaid stretch, a transformerhaving a primary coir stantly supplied with alternating current and two secondaries, means for constantly connecting one said secondary with the rails of said stretch, and means controlled by traffie conditions for at times supplying train controlling current from the other said secondary to at least one rail of said stretch.

.3. Railway traffic controlling apparatus comprising a stretch of railway track, a source of track circuit current for said stretch, a transformer having a primary constantly supplied with alternating current and two secondaries, means for constantly connecting one said secondary with the rails of said stretch at one point in the stretch, and means for at times supplying train controlling current from the other said secondary to a different point in said stretch.

1. Railway traffic controlling apparatus comprising a stretch of railway track, a source of track circuit current for said stretch, a transformer having a primary constantly supplied with alternating current and two secondaries, means for constantly connecting one said secondary with the rails of said stretch at one point in the stretch, a second transformer having a secondary connected with the rails of said stretch at a different pointin the stretch, and a circuit for the primary of said second transformer including the other secondary of said first mentioned transformer and controlled by traflic conditions.

5. Railway traffic controlling apparatus comprising a stretch of railway track having at least one rail thereof provided with' an insulated joint intermediate its ends, a

source of track circuit current for said stretch, a first source of train controlling current connected across said insulated joint, and a second source of train controlling current connected across the rails adjacent one end of said stretch.

6. Railway traffic controlling apparatus comprising a stretch of railway track having at least one rail thereof provided with an insulated joint intermediate its ends, a source of track circuit current for said. stretch, a

first transformer having a primary constantly supplied with. current and two secondaries, means for connecting one said secondary across the rails adjacent one end of said stretch, a second transformer having a secondary constantly connected across said insulated joint, and a circuit for the primary of said second transformer including the remaining secondary of said first transformer.

7. Railway traflic controlling apparatus comprising a stretch of railway track having at least one rail thereof provided with an insulated joint intermediate its ends, a source of track circuit current for said stretch, a

first transformer having a primary constantly supplied with current and two secondaries, means for connecting one said secondary across the rails adjacent one end of said stretch, a second transformer having a secondary constantly connected across said insulated joint a relay connected across the rails of said stretch adjacent said insulated joint and a circuit forthe'primary of said second transformer including the other secondary of said first transformer and a contact of said relay.

In testimony whereof I affix my signature.

HOWARD A. THOMPSON. 

